[oe] Fixing Git mis-information in "Upgrading packages" Wiki page.

[Jacob Helwig]

http://wiki.openembedded.net/index.php/Upgrading_packages has some
pretty big mis-information about git-mv, and git-log, when it comes to
their interaction and how history is presented.

Cleaning up "Upgrading packages" is simple enough, but it seems like it
would be good to have instructions on how to actually follow the history
of a file across copies/renames, since "git mv a b" won't affect how the
history shows up compared to "mv a b && git rm --cached a && git add b"
(since the former is nothing more than short-hand for the latter).

The GitPhraseBook seems like the most appropriate place to add things
about how to get the followed history that usage of git-mv was looking
to provide.

Now that all this preamble is out of the way, we get to the real
question: What kinds of things are people doing, when they're interested
in (potentially) following the history of a recipe?  I'd be more than
happy to update the Wiki with all the use-cases.  I just want to make
sure that I don't miss any that people are looking for.

The ones I can think of off hand are:

    * Examining the your uncommitted changes (both staged, and
      unstaged), and showing potential copies/renames.

    * Showing the history of a branch/tag, and showing potential
      copies/renames.

    * Showing the history of a specific file, while following across
      copies/renames.

    * Blaming/annotating a file, and showing annotations from before a
      copy/rename.

Are there any "phrases" that I've missed that would be good to have in
the GitPhraseBook?

-Jacob